Medical implants

ABSTRACT

The current invention is directed to a medical implant made of bulk-solidifying amorphous alloys and methods of making such medical implants, wherein the medical implants are biologically, mechanically, and morphologically compatible with the surrounding implanted region of the body.

FIELD OF THE INVENTION

The present invention relates to medical implants made ofbulk-solidifying amorphous alloys and methods of making such implants.

BACKGROUND OF THE INVENTION

A medical implant is any implant that embeds or attaches as a mechanicaldevice or part in the tissues or organs of the body to achieve orenhance one or more biological functionality. In some cases suchmechanical devices or parts may completely replace the function of therelevant body parts, such as tissues or organs, and more specifically,the bones, joints, ligaments, and muscles.

One universal requirement of implants, wherever they are used in thebody, is the ability to form a suitably stable mechanical connectionwith neighboring hard or soft tissues. An unstable implant may functionless efficiently, or cease functioning completely, which may induceexcessive tissue response. In addition, it has been recognized that allimplants should achieve a biological functionality, that is, the implantmust meet several requirements for compatibility such as biological,mechanical, and morphological compatibility.

Depending on the primary function of the medical implant, the implantitself can take several forms. For example, in one form implants act asa load-bearing member instead, or in conjunction with, naturalload-bearing members of the body such as bone. In such cases, a highstrength material with an elastic modulus close to that of the bonewhich the implant is replacing or attaching to has been sought. Inanother form implants can be the whole or a part of articulating joints,such as a hip-joint. In such cases, materials with high wear andfretting resistance is desired. In still other forms implants can becheek-bones, tooth implants, skull plates, fracture plates,intra-medullary rods, bone screws, etc.

Generally, the materials chosen for medical implants have been adaptedfor the use from materials developed for applications other than medicalimplants. As a result, such materials have not been always satisfactory.Moreover, the manufacturing of medical implants has also been a majorissue as the fabrication of intricate shapes and surface finishing haseither limited the desired functionality of such implants or increasedthe cost of making such implants substantially.

Accordingly, a new class of materials is needed to address the materialand manufacturing deficiencies of current materials as well as toprovide options and tailorable properties for the various demands ofmedical implants.

SUMMARY OF THE INVENTION

The current invention is directed to a medical implant made ofbulk-solidifying amorphous alloys and methods of making such medicalimplants, wherein the medical implants are biologically, mechanically,and morphologically compatible with the surrounding implanted region ofthe body.

In one embodiment of the invention, the medical implant is made of abulk-solidifying amorphous alloy. In one preferred embodiment of theinvention, the medical implant is made of Zr/Ti base bulk-solidifyingamorphous alloy with in-situ ductile crystalline precipitates. Inanother preferred embodiment of the invention, the medical implant hasbiological, mechanical and morphological compatibility; and is made ofZr/Ti base bulk-solidifying amorphous alloy with in-situ bcc crystallineprecipitates of the base-metal. In another preferred embodiment of theinvention, the medical implant is made of Zr/Ti base bulk-solidifyingamorphous alloy with no Nickel. In still another preferred embodiment ofthe invention, the medical implant is made of Zr/Ti basebulk-solidifying amorphous alloy with no Aluminum. In yet anotherpreferred embodiment of the invention, the medical implant is made ofZr/Ti base bulk-solidifying amorphous alloy with no Beryllium.

In one preferred embodiment of the invention, a medical implant hasbiological, mechanical and morphological compatibility; and is made ofZr/Ti based bulk-solidifying amorphous alloy. In another preferredembodiment of the invention, a medical implant has biological,mechanical and morphological compatibility; and is made of Zr-basedbulk-solidifying amorphous alloy.

In another embodiment of the invention, the medical implant comprises aportion made at least in part of an implantation material other thanbone.

In still another embodiment of the invention, the bulk solidifyingamorphous alloy component of the medical implant is coated with abiocompatible polymethyl methacrylate resin cement, which is reinforcedwith selected oxides including alumina, magnesia, zirconia, or acombination of these oxides along with an application of a small amountof a metal primer agent.

In yet another embodiment of the invention, the medical implantfunctions as a load-bearing member.

In still yet another embodiment of the invention, the medical implantfunctions as at least a portion of an articulating joint. In such anembodiment, the medical implant may comprise an articulating bearingsurface of the joint.

In still yet another embodiment the invention is directed to a method offorming a medical implant. In one such embodiment, a molten piece ofbulk-solidifying amorphous alloy is cast into near-to-net shapecomponent for a medical implant. In another preferred embodiment of theinvention, a feedstock of bulk-solidifying amorphous alloy is heated toaround the glass transition temperature and formed into a near-to-netshape component for a medical implant.

In still yet another embodiment of the invention, the surface of themedical implant is modified by chemical treatment. In such anembodiment, the chemical treatment may use a mixed aqueous solution ofhydrofluoric acid or nitric acid or sodium hydroxide, or a thermaltreatment under in-air oxidation, or a combination of aforementionedtreatments.

In still yet another embodiment of the invention, the surface topographyof the medical implant has pores with a diameter between about 10 to 500□m, preferably between about 100 to 500 □m, and most preferably betweenabout 100 to 200 □m.

In still yet another embodiment of the invention, the surface topographyof the medical implant has an average roughness of between 1 to 50 □m.

In still yet another embodiment of the invention, the surface topographyof the medical implant has a concave texture, convex texture or both.

In still yet another embodiment, the invention is directed to a methodof fabricating a medical implant of a bulk-solidifying amorphous alloys.

In still yet another embodiment, the invention is directed to a methodof duplicating desired morphological features onto the surface of themedical implant.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawing wherein:

FIG. 1 shows a flow-chart an exemplary embodiment of a method ofreproducing surface morphological features on a medical implantaccording to the current invention;

FIG. 2 shows a flow-chart another exemplary embodiment of a method ofreproducing surface morphological features on a medical implantaccording to the current invention;

FIG. 3 shows a flow-chart an exemplary embodiment of a method ofproducing a medical implant according to the current invention; and

FIG. 4 shows a flow-chart another exemplary embodiment of a method ofproducing a medical implant according to the current invention.

DETAILED DESCRIPTION OF THE INVENTION

The current invention is directed to medical implants made ofbulk-solidifying amorphous alloys capable of providing biological,mechanical, and morphological compatibility, and methods of making suchmedical implants.

Bulk solidifying amorphous alloys are a recently discovered family ofamorphous alloys, which can be cooled at substantially lower coolingrates, of about 500 K/sec or less, and substantially retain theiramorphous atomic structure. As such, these materials can be produced inthickness of 1.0 mm or more, substantially thicker than conventionalamorphous alloys of typically 0.020 mm which require cooling rates of10⁵ K/sec or more. Exemplary alloy materials are described in U.S. Pat.Nos. 5,288,344; 5,368,659; 5,618,359; and 5,735,975 (the disclosures ofwhich are incorporated in their entirety herein by reference).

One exemplary family of bulk solidifying amorphous alloys can bedescribed as (Zr,Ti)_(a)(Ni,Cu, Fe)_(b)(Be,Al,Si,B)_(c), where a is inthe range of from 30 to 75, b is in the range of from 5 to 60, and c inthe range of from 0 to 50 in atomic percentages. Furthermore, thosealloys can accommodate substantial amounts of other transition metals upto 20% atomic, and more preferably metals such as Nb, Cr, V, Co. Apreferable alloy family is (Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is inthe range of from 40 to 75, b is in the range of from 5 to 50, and c inthe range of from 5 to 50 in atomic percentages. Still, a morepreferable composition is (Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is inthe range of from 45 to 65, b is in the range of from 7.5 to 35, and cin the range of from 10 to 37.5 in atomic percentages. Anotherpreferable alloy family is (Zr)_(a) (Nb,Ti)_(b) (Ni,Cu)_(c)(Al)_(d),where a is in the range of from 45 to 65, b is in the range of from 0 to10, c is in the range of from 20 to 40 and d in the range of from 7.5 to15 in atomic percentages. These bulk-solidifying amorphous alloys cansustain strains up to 1.5% or more and generally around 1.8% without anypermanent deformation or breakage. Further, they have high fracturetoughness of 10 ksi-sqrt(in) (sqrt: square root) or more, and preferably20 ksi sqrt(in) or more. Also, they have high hardness values of 4 GPaor more, and preferably 5.5 GPa or more. The yield strength of bulksolidifying alloys range from 1.6 GPa and reach up to 2 GPa and moreexceeding the current state of the Titanium alloys. Further, Zr-basebulk-solidifying amorphous alloys have a generally lower modulus ofelasticity than Ti-base bulk-solidifying amorphous alloys, and have morerobust processibility characteristics, which allows a better casting ofthe desired micro-structured surface features.

Another set of bulk-solidifying amorphous alloys are ferrous metals (Fe,Ni, Co) based compositions. Examples of such compositions are disclosedin U.S. Pat. No. 6,325,868; (A. Inoue et. al., Appl. Phys. Lett., Volume71, p 464 (1997)); (Shen et. al., Mater. Trans., JIM, Volume 42, p 2136(2001)); and Japanese patent application 2000126277 (Publ. #0.2001303218A), all of which are incorporated herein by reference. One exemplarycomposition of such alloys is Fe₇₂Al₅Ga₂P₁₁C₆B₄. Another exemplarycomposition of such alloys is Fe₇₂Al₇Zr₁₀Mo₅W₂B₁₅. Although, these alloycompositions are not processable to the degree of the above-citedZr-base alloy systems, they can still be processed in thicknesses around1.0 mm or more, sufficient enough to be utilized in the currentinvention. Similarly, these materials have elastic strain limits higherthan 1.2% and generally around 1.8%. The yield strength of theseferrous-based bulk-solidifying amorphous alloys is also higher than theZr-based alloys, ranging from 2.5 GPa to 4 GPa, or more. Ferrousmetal-base bulk amorphous alloys also very high yield hardness rangingfrom 7.5 GPA to 12 GPa.

In general, crystalline precipitates in bulk amorphous alloys are highlydetrimental to the properties of bulk-solidifying amorphous alloys,especially to the toughness and strength of these materials, and, assuch, such precipitates are generally kept to as small a volume fractionas possible. However, there are cases in which, ductile crystallinephases precipitate in-situ during the processing of bulk amorphousalloys, are indeed beneficial to the properties of bulk amorphousalloys, and especially to the toughness and ductility of the materials.Such bulk amorphous alloys comprising such beneficial precipitates arealso included in the current invention. An exemplary composition of suchalloy is Zr_(56.2)Ti_(13.8)Nb_(5.0)Cu_(6.9)Ni_(5.6)Be_(12.5) in atomicpercentages. This alloy has a low elastic modulus of from 70 GPa to 80GPa depending on the specific microstructure of ductile-crystallineprecipitates. Further, the elastic strain limit is 1.8% or more and theyield strength is 1.4 GPa and more.

Although a number of bulk solidifying amorphous alloy compositions aredescribed above, the alloy can also be preferably selected to be free ofNi or Al or Be in order to address high sensitivity or allergy ofspecific population groups to such metals.

Applicants have discovered that bulk-solidifying amorphous alloys havegeneral characteristics, which are particularly useful in medicalimplants. These characteristics, as will be shown below, makebulk-solidifying amorphous alloys uniquely suited as a class ofmaterials for use in medical implants.

First, bulk-solidifying amorphous alloys have an elastic modulus that istypically 15 to 25% lower than the conventional alloys of itsconstituent elements. This decreased elastic modulus is the directresult of the amorphous atomic structure of the alloys, which lackslong-range atomic order as in the case of conventional crystallinemetals. For example, a titanium base crystalline alloy (such as Ti-6-4,which is commonly used in medical implants) has an elastic modulustypically around 120 GPa, whereas Ti-base amorphous alloys have anelastic modulus around or below 100 GPa. This decreased elastic modulusis particularly desirable because bone has an elastic modulus of about20 GPa or less, and implant materials with an elastic modulus closer tothe elastic modulus of bone have better biological functionality,especially when the implant is used as a load-bearing member.Specifically, the better the match between the elastic modulus of theimplant material and the elastic modulus of the replacement bone, thebetter the implant will integrate with the surrounding or associatedbone, and function in a more coherent manner, thereby allowing thesurrounding or associated bones to absorb a fair share of the stressloading. However, where materials with relatively high elastic modulusare used, the surrounding or associated bones will take less of theloading, and as a result will not be able to function in their normalmanner, and ultimately may cause bone-thinning or failure of theimplant.

Secondly, bulk-solidifying amorphous alloys typically have yieldstrengths of at least 50% higher than conventional alloys of made ofsimilar constituent elements. For example, a titanium base crystallinealloy (such as Ti-6-4, which is commonly used in medical implants) has ayield strength typically around 850 MPa, whereas Ti-base amorphousalloys have a yield strength around 1900 MPa. The combination of suchlow modulus and high yield strength makes it possible to manufacture adurable and strong load-bearing medical implant with high mechanicalfunctionality.

Further, bulk solidifying amorphous alloys have a very high elasticstrain limit, which characterizes a material's ability to sustainstrains without permanent deformation. Typically bulk-solidifyingamorphous alloys have elastic strain limits of around 1.8% or higher.The elastic strain limit is another important characteristic ofmaterials for use in medical implants, and one that is of particularimportance for implant members subject to any mechanical loading.However, conventional implant materials generally have very poor elasticstrain limit properties. For example, conventional metals and alloysused as implant materials have elastic strain limit below 0.9%, whichindicates that these materials are not able to sustain very large globaland local loading without some minimal or even permanent deformation ofthe implant material. A high elastic strain limit also helps to maintainthe surface morphology of the implant and, as such, precludes excessivetissue response. In the case of conventional metals and alloys with verylow elastic strain limits, the use of larger and much more rigidimplants is generally needed to sustain both loading on global and localloading as well as to maintain the integrity of the implant's surfacemorphology. However, larger implants and rigid implant structures arehighly undesirable because of the increased operational and surgicalcomplications from implementing larger implant structures as well as“bone thinning” in the associated bones.

Another important requirement for an implant material is to have asuitable surface morphology. For example, in a scientific articlepublished by Oshida (“Fractal Dimension Analysis Of Mandibular Bones:Toward A Morphological Compatibility Of Implants” in Bio-MedicalMaterials and Engineering, 1994, 4:397-407), the disclosure of which isincorporated herein by reference, it was found that surface morphologyof successful implants has upper and lower limitations in averageroughness (1˜50 μm) and average particle size (10˜500 μm), regardless ofthe type of implant material (metallic, ceramics, or polymericmaterials) used. For example, it has been shown that if an implantmaterial has a particle size smaller than 10 μm, the surface of theimplant will be more toxic to fibroblastic cells and have an adverseinfluence on cells due to their physical presence independent of anychemical toxic effects. Likewise, if the pore size of the implantmaterial is larger than 500 μm, the surface does not exhibit sufficientstructural integrity because it is too coarse. Therefore, morphologicalcompatibility is an important factor in implant design, and is now wellaccepted in the field of implants.

Unfortunately due to the small dimensions of acceptable morphologicalfeatures, desired surface morphology cannot be readily produced ontocurrent implant materials. Instead, mechanical and chemical methods,such as shot peening and acid etching, are used to fabricate surfacemorphology onto the implant material after the shaping and fabricationof the actual implant body. Because of the statistical nature of theseconventional only surface morphologies with relatively crude and randomfeatures and lacking consistency and precision both in the shape and thedistribution of desired surface features have been produced. Indeed, theproduction of suitable surface morphologies can be said to be the resultof statistical accidents rather than by design.

Applicants have found that it is possible to form micro-structuredsurface morphologies by design using bulk-solidifying amorphous alloys.The unique amorphous atomic microstructure of these materials respondsuniformly to the forming operations of micron and sub-micron scalemaking it possible to form features within the desirable morphologicalranges. This is in distinct contrast to conventional metals and alloys,where the microstructure of the material is characterized bycrystallites (individual grains typically with dimensions of few toseveral hundreds microns) each of which has different crystallographicorientation and, as such, responds non-uniformly to shaping and formingoperations.

The micro-structured surface morphology according to the currentinvention can be produced in two alternative ways. In a first exemplarymethod, as outlined in FIG. 1, the surface morphology can besimultaneously formed during the fabrication of implant components bycasting methods. In such an embodiment the mold surfaces used in thecasting operation can be pre-configured to have the negative impressionof the desired surface microstructure so that the bulk-solidifyingamorphous alloy replicates such features upon casting. The relativelylow melting temperature of bulk-solidifying amorphous alloys and thelack of any first-order phase transformation during the solidificationreadily enables the replication of micron sized mold features during thecasting of the implant components. The solidification shrinkage is thendominated by the coefficient of thermal expansion rather than the volumedifference between the solid and liquid state of the casting alloy.Accordingly, bulk amorphous alloys with low coefficients of thermalexpansion (at temperatures from ambient to glass transition) arepreferred. For example, Zr-base bulk solidifying amorphous alloysgenerally have a coefficient of thermal expansion of around 10⁻⁵ (m/m °C.) providing low shrinkage rates. Such a process is highly desirable asseveral steps of post-finishing and surface preparation operations canbe reduced or eliminated.

In an alternative exemplary method, as outlined in FIG. 2, apre-fabricated implant component made of bulk-solidifying amorphousalloy is subjected to a surface micro-structuring process at around theglass transition temperature of the bulk-solidifying amorphous alloymaterial. In such an embodiment, the fabricated implant component isheated to around the glass transition temperature and pressed against amold having the negative impression of the desired surfacemicrostructure. Alternatively, a mold heated around about the glasstransition temperature of the amorphous alloy can be brought intocontact with the fabricated implant component to make a surfaceimpression and form the micro-structured surface features. As the bulksolidifying amorphous alloy will readily transition into a viscousliquid regime upon heating, the replication of the desired surfacemorphology can readily take place. In this embodiment of the method,bulk-solidifying amorphous alloys with a large ΔTsc (supercooled liquidregion) are preferred. For example, bulk-solidifying amorphous alloyswith a ΔTsc of more than 60° C., and still more preferably a ΔTsc of 90°C. and more are desired for their ability to reproduce high-definitionsurface micro-structuring. One exemplary embodiment of an alloy having aΔTsc of more than 90° C. is Zr₄₇Ti₈Ni₁₀Cu_(7.5)Be_(27.5). ΔTsc isdefined as the difference between Tx (the onset temperature ofcrystallization) and Tsc (the onset temperature of super-cooled liquidregion). These values can be conveniently determined by using standardcalorimetric techniques such as by DSC measurements at 20° C./min.

Regardless of the method utilized, the surface micro-structure can takeseveral forms depending on the specific application. For example, in oneembodiment, the surface microstructure can have relatively minutefeatures (such as with typical dimensions of around 10 microns). Inanother embodiment, the surface feature can have gross features (such aswith typical dimensions of around 100 microns or more). In this lattercase, the surface can be subjected to other surface treatments, such aschemical treatment to further improve the surface morphology. It shouldfurther be understood that, the bulk-solidifying amorphous alloys may beprocessed to produce consistent and precise surface microstructures ofboth currently known and used morphologies, and also novel surfacemorphologies unavailable in current medical implant materials.

The composition of bulk-solidifying amorphous alloys can be selected toaddress specific needs for various implants. For example, Zr/Ti basebulk-solidifying amorphous alloys are preferred for improved corrosionresistance and bio-compatibility. Zr-base bulk-solidifying amorphousalloys are especially preferred for still lower elastic modulus.

This invention is also directed to methods of fabricating medicalimplants of bulk-solidifying amorphous alloys. In a first exemplaryembodiment, as outlined in FIG. 3, the medical implants may befabricated by a casting process as described in the following. Afeedstock of bulk-solidifying amorphous alloy (Step 1) is provided,which does not necessarily have any amorphous phase. The feedstock isthen heated above the melting temperature (Step 2) of thebulk-solidifying amorphous alloy and the molten alloy is then introducedinto a suitable mold (Step 3) having the shape of the desired medicalimplant. The molten alloy can be introduced into the mold by variousmeans such as by injection of gas or piston pressure, by vacuum suction,and vacuum assisted counter gravity casting. The molten alloy is thenquenched (Step 4) at cooling rates sufficient to form a substantiallyamorphous phase having an elastic strain limit of 1.5% or higher. Themold surface can have the negative impressions of the desired morphologyas described above. This process allows the production of high-strengthmedical implant components with near-net-shape tolerances to the actualcomponent, and, as such, substantial cost savings can be achieved byreducing the post-casting process (Step 5) and achieving closertolerances to the actual component. The provided bulk solidifyingamorphous alloy is such that, it has a critical cooling rate of lessthan 1,000° C./sec, so that section thicknesses greater than 0.5 mm canbe readily cast into an amorphous structure during the fabrication of adental prosthesis. However, more preferably, the critical cooling rateis less than 100° C./sec and most preferably less than 10° C./sec. Inone preferred embodiment of the invention, the dental prosthesis is castby providing a bulk-solidifying amorphous alloy having a coefficient ofthermal expansion of less than about 10⁻⁵ (m/m ° C.), and a glasstransition temperature of less than 400° C., and preferably less than300° C., in order to achieve a high level of replication of prosthesismold features after casting.

In an alternative method, as outlined in FIG. 4, a substantiallyamorphous feedstock of a bulk-solidifying amorphous alloy is provided(Step 1). The feedstock is then heated around the glass temperature ofthe bulk-solidifying amorphous alloy to reach the viscous-fluid regime(Step 2). The viscous alloy is then forced against or onto a suitablemold (Step 3) having the shape of the desired medical implant. When thedesired implant shape is formed, the viscous alloy is then quenched(Step 4) to retain the substantially amorphous phase having an elasticstrain limit of 1.5% or higher. The mold surface can have the negativeimpressions of the desired morphology as described above. Again, thisprocess also allows producing high-strength medical implant componentswith near-net-shape tolerances to the actual component, and, as such,substantial cost savings can be achieved by reducing the post-castingprocess (Step 5) and achieving closer tolerances to the actualcomponent. In this embodiment of the method, bulk-solidifying amorphousalloys with a large ΔTsc (supercooled liquid region) are preferred.Again, for example, bulk-solidifying amorphous alloys with a ΔTsc ofmore than 60° C., and still more preferably a ΔTsc of 90° C. and moreare desired because they possess the desired mechanical properties, suchas high-elastic strain limit, and because of the ease of fabricatingthese materials.

Furthermore, permanent molds, such as metallic dies, can be employed inthe above mentioned processes of fabricating implant components andsurface micro-structuring processes. Such use of permanent molds in thefabrication of high strength implant components is unique tobulk-solidifying amorphous alloys. Generally, such permanent moldprocesses with high-strength conventional materials are not suitable forthe fabrication of implant components, as various issues such as severereaction with mold, casting defects, micro-structural uniformity, andproper mold fill can not be satisfactorily addressed. Accordingly, theuse of permanent mold provides distinct advantages to bulk-solidifyingamorphous in the use and method of fabrication for medical implants, ashigher through-put, better consistency, both in general dimensions andsurface morphology, and lower fabrication costs can be achieved.

Although specific embodiments are disclosed herein, it is expected thatpersons skilled in the art can and will design medical implants andmethods of making such devices that are within the scope of thefollowing description either literally or under the Doctrine ofEquivalents.

1-36. (canceled)
 37. An object for placement into a region comprising: abody at least partially constructed of a bulk-solidifying amorphousalloy having an elastic strain limit of around 1.2% or more, saidbulk-solidifying amorphous alloy having a composition that is free fromNi; wherein the body has a plurality of micro-structured surfacefeatures on an outer surface thereof, wherein the micro-structuredsurface features have an average roughness and a surface morphology suchthat the outer surface of the body has mechanical and morphologicalcompatibility with the region.
 38. The object of claim 37, wherein themicro-structural features on the outer surface of the body comprise aplurality of pores with diameters between about 10 to 500 μm.
 39. Theobject of claim 37, wherein the micro-structural features arereplications of sub-micron or micron sized mold features on the outersurface of the body.
 40. The object of claim 37, wherein themicro-structural features have morphological features having dimensionsin a micron scale range or a sub-micron scale range.
 41. The object ofclaim 37, the outer surface of the body has an average roughness ofbetween 1 to 50 μm.
 42. The object of claim 37, wherein themicro-structural features on the outer surface of the body comprise asurface texture selected from the group consisting of concave, convex,and mixture of concave and convex.
 43. The object of claim 37, whereinthe bulk-solidifying amorphous alloy is described by the followingmolecular formula: (Zr,Ti)_(a)(Ni,Cu,Fe)_(b)(Be,Al,Si,B)_(c), wherein“a” is in the range of from about 30 to 75, “b” is in the range of fromabout 5 to 60, and “c” in the range of from about 0 to 50 in atomicpercentages, wherein the alloy is free from at least one materialselected from the group consisting of Ni, Be and Al.
 44. The object ofclaim 37, wherein the bulk-solidifying amorphous alloy is describedsubstantially by the following molecular formula:(Zr)_(a)(Nb,Ti)_(b)(Cu)_(c)(Al)_(d), where a is in the range of from 45to 65, b is in the range of from 0 to 10, c is in the range of from 20to 40, and d in the range of from 7.5 to 15 in atomic percentages. 45.The object of claim 37, wherein the bulk-solidifying amorphous alloy hasan elastic strain limit of around 1.8% or more.
 46. The object of claim37, wherein the bulk-solidifying amorphous alloy has a high fracturetoughness of at least about 10 ksi-in.
 47. The object of claim 37,wherein the bulk-solidifying amorphous alloy has a high hardness valueof at least about 5.0 GPa.
 48. The object of claim 37, wherein thebulk-solidifying amorphous alloy is based on ferrous metals.
 49. Theobject of claim 37, wherein the bulk-solidifying amorphous alloycomprises Zr and Ti, and further comprises a ductile metalliccrystalline phase precipitate.
 50. The object of claim 37, wherein thebulk-solidifying amorphous alloy is Al, or Be free.
 51. The object ofclaim 37, wherein the portion of the body formed from thebulk-solidifying amorphous alloy has a section thickness of at least 0.5mm.
 52. The object of claim 37, wherein the body is in the form of aload bearing member.
 53. The object of claim 37, wherein the body is inthe form of an articulating joint.
 54. The object of claim 37, whereinthe bulk-solidifying amorphous alloy has a supercooled liquid region ofmore than 90° C.
 55. The object of claim 37, wherein thebulk-solidifying amorphous alloy comprises Be.